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PM S45VN is a premium martensitic stainless steel engineered to provide
enhanced corrosion and wear resistance compared to CPM S35VN. Through meticulous rebalancing of its chemistry, more chromium carbides are formed, while ensuring ample free chromium in the matrix. By incorporating Niobium and Nitrogen instead of some Vanadium and Carbon, CPM S45VN achieves an exceptional balance of edge retention, wear resistance, corrosion resistance, and toughness, making it the ultimate choice for everyday carry (EDC) knife steel.
The
CPM process yields extremely homogeneous, high-quality steel that excels in dimensional stability, grindability, and toughness, significantly outperforming steels produced through conventional melting techniques.
Typical Applications:
Long-Wearing Specialty Cutlery Plastic Injection and Extrusion Feed Screws and Dies Non-Return Valve Components Pelletizing Equipment Wear Components for Food and Chemical Processing Note: These are general applications. Conduct an independent study and evaluation for the suitability of your specific application.
Chemical Composition:
Physical Properties:
Elastic Modulus32 X 10^6 psi
(221 GPa)
Density 0.27 lbs./in^3
(7.47 g/cm^3)
Thermal Conductivity
BTU/hr-ft-°F
W/m-°K
cal/cm-s-°C
200°F
93°C
10
17.31
4.13 X 10^-2
Coefficient of Thermal Expansion
°F
°C
in/in/°F
mm/mm/°C
7
0 - 400
(20 - 200)
6.1 X10^-6
(11.0 X10^-6)
70 - 600
(20 - 315)
6.4 X10^-6
(11.5 X10^-6)
Mechanical Properties:
Toughness (Transverse Charpy C-notch Testing)
Though all four grades exhibit longitudinal toughness around 25-28 ft. lbs., the transverse toughness of CPM grades is at least four times greater than 440C and 154CM. This superior transverse toughness indicates that CPM S45VN, CPM S35VN, and CPM S30V are significantly more resistant to chipping and breaking under lateral stress. In knifemaking, this translates to CPM being particularly advantageous for larger blades.
Edge Retention (CATRA Testing Relative to 440C)
T
The CATRA (Cutlery & Allied Trades Research Association) test machine executes a standardized cutting operation to measure the endurance by counting the number of silica-impregnated cards sliced. This metric is widely regarded as a benchmark for relative wear resistance and is presented here in comparison to a 440C standard. *Estimate based upon market feedback.
Thermal Treatments::
Forging:
Heat to 2100°F (1150°C). Avoid forging below 1750°F (950°C).
Annealing:
Heat to 1650°F (900°C) and hold for 2 hours. Then, cool slowly at a rate no faster than 25°F (15°C) per hour until 1100°F (595°C). Follow this by furnace cooling or still air cooling to room temperature.
Annealed Hardness: Approximately BHN 255.
Stress Relieving Annealed Parts:
For annealed parts, heat to 1100-1300°F (595-705°C) and hold for 2 hours, followed by furnace cooling or still air cooling. For hardened parts, heat 25-50°F (15-30°C) below the original tempering temperature, hold for 2 hours, and then allow to furnace cool or cool in still air.
Straightening:
Best performed warm at 400-800°F (200-425°C).
Hardening Preheat:
Heat to 1550-1600°F (845-870°C) and equalize. Austenitize by heating to 1900-2000°F (1035-1095°C) and hold at temperature for 15-30 minutes. Quench by air or positive pressure (minimum 2 bar) to below 125°F (50°C), or use salt or interrupted oil quenching to approximately 1000°F (540°C), then air cool to below 125°F (50°C).
Temper:
Double temper between 400-750°F (200-400°C). Hold for a minimum of 2 hours each time. Optionally, use a freezing treatment between the first and second tempers to achieve maximum hardenability, followed by at least one temper.
NOTE: For optimum stress relieving, temper CPM S45VN at 1000-1025°F (540-550°C). Be aware that tempering in this range may slightly reduce corrosion resistance.
Size Change:
Expect a size increase of +0.05 to +0.10% when fully martensitic. Retained austenite may reduce net growth. Freezing treatments may be required to minimize retained austenite when tempering at 400-750°F (200-400°C).
Recommended Heat Treatment:
Austenitize at 1950°F (1065°C). Quench to below 125°F (50°C). Double temper at 600°F (315°C) for a minimum of 2 hours each. Cool to hand warmth between tempers. Optionally, use a freezing treatment between tempers.
Target Hardness: Aim for 59-61 HRC.
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